Push-button switches in motor vehicles are able to be found easily in the dark when a symbol on the operating surface of the push-button is illuminated by a symbol lighting arrangement. Generally, the symbol is illuminated when the headlights of the vehicle are switched on. With some push-button switches, it is efficient to inform the vehicle occupant of the current switching status of the push-button switch, e.g. as to whether a functional unit is switched on or off. An additional function lighting arrangement can be provided for this, having a outlet area in the push-button which is illuminated separately from the symbol lighting only as a function of the operating status of the functional unit which is to be operated.
In EP-A-1 107 268 a push-button switch is shown, which is part of a switch unit having several key switches. The push-button switch includes a housing and a push-button. The push-button switch further includes are symbol lighting arrangement to illuminate a transparent region of the push-button. The transparent region symbolizes the functional unit to be operated by the push-button switch. The push-button switch further includes a function lighting arrangement to indicate the operating status of the functional unit. The symbol lighting arrangement comprises a first light source and the function lighting arrangement comprises a second light source and an off-portioned light conducting section to a light outlet area. The light conducting section is integrated into the push-button. An incandescent bulb arranged outside the housing of the switch unit serves both for external “floodlight illumination” of the switch unit and also to illuminate the function symbols of the individual push-buttons. For this, the light of the incandescent bulb is directed via light conductors back into the housing and to the respective function symbols. This design is inefficient, however, for individual push-button switches and requires additional structural space. In addition, this solution is not suitable for applications in which an external illumination of the push-button switches could be felt to be intrusive.
It is an object of the invention to provide a compact electric push-button switch with efficient symbol and function lightings.